


Against, Into, Under

by relucant



Series: Grammar Games [1]
Category: Supernatural
Genre: Alternate Universe - High School, Blow Jobs, Bottom Dean, Grammar Porn, Library Sex, M/M, Nerd Castiel, Nobody's a Dick, Popular Dean, Public Blow Jobs, Spelling & Grammar, Tutoring
Language: English
Status: Completed
Published: 2015-01-20
Updated: 2015-01-20
Packaged: 2018-03-08 10:31:41
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,510
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3206006
Author URL: https://archiveofourown.org/users/relucant/pseuds/relucant
Summary: <blockquote class="userstuff">
              <p>"Hey, hey," Dean said, propping his feet up on a chair.  "Dude, I don't even know your <i>name</i>."</p><p>Cas blinked up at him, and the tiny heat that the gravelly voice had sparked in Dean's stomach evolved into a full-on tingle.</p><p>"Oh, uh," he said.  "Yeah.  I'm Castiel.  Cas, if you like."</p><p>"Cas," Dean drawled.  "I do like."  He stuck out his hand.  Cas raised an eyebrow, but he reached out to shake.  "I'm Dean Winchester."</p><p>"I'm aware," Cas said dryly.  "You've something of a reputation."</p><p>"I'm aware," Dean agreed with a bright grin.</p>
            </blockquote>





	Against, Into, Under

**Author's Note:**

  * For [Eveanyn](https://archiveofourown.org/users/Eveanyn/gifts), [LoversAntiquities](https://archiveofourown.org/users/LoversAntiquities/gifts).



>  
> 
>  
> 
> banners by the lovely [mayalaen](http://mayalaen.tumblr.com) for my birthday! <3

Dean tossed his backpack onto the library table and sighed, eyeing the kid across from him. He still wasn't sure how a _junior_ was supposed to tutor him in senior English, but as he looked over the messy head of dark hair and pink lips, down over the clean lines of his body under the tight t-shirt and black jeans, he decided he was pretty on board with this intrusion into his academic success.

"OK," the guy mumbled, pushing up his glasses and flipping open a textbook. "Um --"

"Hey, hey," Dean said, propping his feet up on a chair. "Dude, I don't even know your _name_."

Cas blinked up at him, and the tiny heat that the gravelly voice had sparked in Dean's stomach evolved into a full-on tingle.

"Oh, uh," he said. "Yeah. I'm Castiel. Cas, if you like."

"Cas," Dean drawled. "I do like." He stuck out his hand. Cas raised an eyebrow, but he reached out to shake. "I'm Dean Winchester."

"I'm aware," Cas said dryly. "You've something of a reputation."

"I'm aware," Dean agreed with a bright grin. "So which parts have you heard, good or bad?"

Cas shrugged. "Some of both, I suppose." He pulled back his hand and went back to the book. "So what are you currently working on?"

"Uh, Unit 7. I think."

Cas paged through it, then looked up, confused. "Prepositions? Dean, that's, like, middle school grammar. What --?"

"Uh, yeah, if they _teach_ you it in middle school," Dean snapped, rubbing the back of his neck. "Which they didn't. In case you ain't aware, we live in _Georgia_."

Cas flinched. "I apologize. I, um, I grew up in New England. I didn't mean to imply --"

"Mm, prep school boy?" Dean teased, but Cas flushed and nodded. "Shit, really? An' I guess Mommy and Daddy couldn't find a nice academy down here in bumfuck, so you get stuck shipped off to public school?"

He half-regretted his snotty words as soon as they were out, but to his surprise, Cas just laughed softly. "Believe me, I did not complain."

"Huh," Dean said, eyeing him. "So when'd you move here?"

"Only last month," Cas admitted. "Dean, we --"

"Last month?" Dean said, leaning back and smirking. "So that's why I hadn't noticed you."

Cas' blush deepened, but he sighed. "We _do_ actually have to study, Dean."

"All right, all right," Dean said with an exaggerated sigh. He pulled the textbook over, running his hand down the page. "Look. 'A preposition describes other words in a sentence.' Don't, like, _all_ words describe other words in a sentence? Doesn't a verb describe what a noun does?"

Cas blinked at him, confused, then tugged the book back. "It _says_ that?" He scanned the book, then looked up, appalled. "Jesus. No wonder you --"

"Are a complete idiot?" Dean said flatly, leaning against the chair. "Yeah, no kiddin'."

Cas frowned. "No one is an _idiot_ for not having learned things that their schools did not teach them. That's their failure, not yours."

Dean snorted, and Cas sighed. "Anyway. Prepositions are relatively simple, even if they're poorly explained here." He paused, chewing his lip. "They modify nouns and verbs like adjectives and adverbs do, but within the context of a phrase, and usually referring to a noun or pronoun." He glanced up, and Dean was tapping thoughtfully on the table.

"So that's why they're adjectivial and adverbial?"

"Exactly," Cas said, smiling at him.

"Jesus, couldn't they've said that in the textbook?" Dean grumbled. He pushed his hair off his forehead, and Cas found his eyes tracking the motion. "OK, but -- I sorta get the phrase thing, but -- prepositions themselves, what're --?"

Cas couldn't help grinning at him. " _Aboard, about, above, across, after, against, along, amid, among, around, at_ ," he recited. Dean watched him, eyes slightly dilated. Cas coughed, shifting uncomfortably, because no way _Dean Winchester_ would be interested in -- but he continued with a slight smile, lowering his voice. " _Before behind below beneath beside between beyond by._ "

Dean pulled his leg back under the table and tucked it under his chin. "Not sure if I'm actually learnin' anything here, but I'll listen to you read along all day." He tilted his head back and closed his eyes.

Cas stared at him. "Dean…"

"Mm," Dean said. He nudged his free foot against Cas' and stretched. "Keep goin'."

" _Down_ ," Cas managed. " _Down during except for from in into_ \--"

Dean let his sneakered foot trail up Cas' leg, and Cas clenched the edge of table.

"Dean," he hissed. "We have to --"

"Aw, it's our first day," Dean pointed out, inching his foot up Cas' thigh. "Nobody ever gets shit done the first day."

"We only _have_ a few weeks," Cas said, and reluctantly shoved Dean's foot off. "You must learn this."

"Well, then you gotta _help_ me learn it," Dean said, reasonably. "I mean, I'm a visual dude." He winked. "I don't get much from things just parrotted in my ear."

Cas frowned, looking back down to the book. "There are examples in here we can look at, if that would --"

" _Booo-oooriiing_ ," Dean drawled. "Let's play a game."

"I'm afraid I don't know any grammar games, but I have my laptop, I'm sure we --"

"Nah," Dean interrupted. "Let's just make somethin' up. Like…" He paused, chin on his hand and mischief in his leaf-green eyes, and Cas swallowed. "Like charades."

"Charades?" Cas repeated blankly.

"Uh, yeah? Stupid party game, y'know? Oh, right, your parties were probably all spent sippin' tea and talkin' Shakespeare over crumpets."

He smirked, and Cas stuck his tongue out at him.

"At," Dean said immediately. Cas stared at him like he'd grown a second head. "You stuck your tongue out _at me_. I win."

He crossed his arms with a smug smile, and Cas groaned, but he couldn't quite bite back a laugh, and he had to admit it was kind of clever.

"Fine. Adjectivial or adverbial?"

Dean paused, frowning slightly. "Adjective," he finally announced. "'Cause it modifies your tongue." He winked.

Cas snorted. " _Bzzzt_ ," he said, imitating a buzzer. "No bonus point for you."

"But why…"

"It doesn't modify _tongue_ ; it modifies the action of sticking your tongue out. I didn't _tongue at you_ , I --" He stopped himself, blushing as he replayed his last words, and Dean smirked. "Anyway," he continued, clearing his throat. "The best way to tell the difference is that adjectivial phrases answer the questions _what_ or _which_ , while adverbial phrases answer _how_ or _where_ or _when_. _Where_ did I stick my tongue out? _At_ you." He paused, then grinned, leaning forward slightly, because hell if he was going to let this stupid perfect boy in front of him have _all_ the fun. "So, conversely, for an adjectivial phrase, it might be -- _which_ tongue? The tongue _in your mouth_."

Dean choked slightly before sputtering into a laugh. "So maybe you're not just a little prep school prude," he said. "Good to know." 

Cas' cheeks warmed, and he looked down, surprised at his own nerve.

"Anyway," Dean continued, "my turn." He stared at Cas consideringly, and Cas was just beginning to wonder how to backpedal when he felt Dean's foot on his calf again, now shoeless, rubbing slow circles. Cas let out his breath in a whoosh, trying to ignore the increasing discomfort in his jeans.

"A-against," he managed. "Against my leg."

"Mm," Dean agreed, his voice noticeably lower. "Adverbial again, right? Where is my foot rubbing? -- It's rubbing against your leg."

"Yes," Cas said, though at this point Dean could have been speaking Spanish and he'd have agreed. He took a deep breath, reminding himself that it was just a silly game.

He pointed to the textbook, the most innocuous gesture he could think of.

"Well, that's just cheating," Dean declared. "'Cause you could be asking _which_ textbook," tapping his finger on the page, "or _where_ it is," tapping the table, "or what you're _pointing at_." With that he hooked his index around Cas'.

"I, um," Cas mumbled. "I think you have the idea."

"You're a pretty good teacher," Dean agreed. "Just a little more practice, 'kay?" He moved his foot up until it was in the middle of Cas' chair. It was barely grazing his crotch, but Cas knew Dean could feel the hard outline of his dick, and he closed his eyes, torn between humiliated and just humiliatingly turned on.

"Bet-between," he grit out.

Dean pressed harder and Cas' eyes shot open. A faint flush had finally crept into Dean's cheeks, highlighting the scattering of freckles, and his eyes were dark. Cas' gaze dropped to his lips, wet and pink and parted.

"Between what, Cas?"

"My legs," he gasped. "Between my legs." He weakly tried to knock Dean's foot away, but instead just ended up pushing his cock against it, and he bit back a groan.

"At," Dean said in a whisper.

"I -- what -- I didn't --"

"At my mouth," Dean clarified. "You're staring _at_ my mouth."

"God, I'm -- I'm sorry, I'm --" he stuttered, but Dean's gaze just flicked between his eyes and lips, still toeing gently between his legs.

"Around," Dean finally said, and Cas blinked at him confusedly through the haze of arousal. "I'm imaginin' my lips _around_ your dick." He pressed his foot in purposefully, and Cas distantly decided that he must be dying, because nothing in his prep school life had remotely prepared him for Dean Winchester. "You want me _under_ the table, Cas?"

"Dean, we're in the library," Cas said desperately. He tried to push his chair back, before realizing belatedly that his fingers were still hooked into Dean's.

"Yeah?" Dean said. "You said you know my rep, man, you think I never given a blowjob in the library?" He paused for a moment, looking thoughtful. "Actually, I haven't," he said, sounding slightly surprised. "All the more reason to, yeah?"

He took his foot back, and Cas' hips jerked at the loss of friction, but then Dean was sliding sinuously off of his chair, crawling under the table until his chin was nudging at Cas' knees.

"Dean, no, we -- we can't --"

"Don't worry, I'll be very discreet," Dean promised with a feral grin, but then he sat back slightly. "You -- you _are_ into this, right? I mean, it _looks_ like you are," with a pointed glance at his crotch, "but seriously, dude, you say the word an' I'll stop, we can go back to studyin', no hard feelings."

"No!" Cas said, far too quickly. "I -- no, yes, I -- I'm into it. Just -- overwhelmed."

"You done this before?" Dean asked curiously, toying with the button of Cas' jeans.

"I -- yes, a few times, but it wasn't very good," Cas admitted, thinking of the handful of late-night experimenting he'd done with his weirdo British roommate.

"Prep school boys," Dean said with a dramatic sigh. "Don't worry, I'll fix that." Without further preamble he yanked Cas' jeans and boxers down his thighs and wrapped his lips around the head of his dick.

"Oh fuck," Cas whispered, biting back an embarrassing whimper.

"So you _do_ curse," Dean murmured, pulling off slightly. "God, you get hotter an' hotter." He leaned back in and licked a slow stripe from root to tip, savoring the way Cas' thigh muscles jumped under his hand. "Jesus, wanna see you naked."

"N-not here," Cas croaked, and Dean choked out a laugh.

"No," he agreed. "Not here." He mouthed at the head of Cas' cock for a second before sinking down, taking him in inch by inch until it hit the back of his throat, then reached up and grabbed Cas' hand, settling it in his hair.

"Fuck," Cas breathed again. He twisted his hand in Dean's hair and Dean moaned, sending ripples of pleasure up his spine. "Do you like that?" He did it again, harder, and Dean groaned an obvious sound of assent, his eyes slipping closed.

Cas' hips jerked automatically and Dean choked slightly, pulling off.

"Shit," Cas whispered, freezing. "Sorry, sorry, I'm --"

Dean wiped his mouth, but the open want in his eyes had intensified. "S'cool," he said. "Just wasn't expectin' that. But go for it."

Cas opened his mouth to protest, but then Dean was sinking back down, taking him into his throat.

" _Fuck_ ," Cas hissed. He brought up his free hand to bite down on the knuckle, stifling the noises threatening to get out, then began thrusting shallowly, and Dean made approving sounds in his throat.

"Dean, I'm going to -- I'm gonna --"

Dean locked eyes with him and gave the barest nod, then swallowed around him once, and Cas was gone, arching, his teeth sunk into the meat of his palm and his other hand on the back of Dean's neck, coming desperately in silent spurts down his throat.

Finally he sank back down to the chair, gasping. Dean pulled off slowly, snaking his tongue gently around his softening cock, then tucked him back into his pants and did them up neatly before sliding back up into his chair.

"Well, that wasn't the worst tutoring session I've had," he rasped, licking his lips and looking for all the world like the cat who got the cream.

Cas just nodded dumbly, trying to get his breathing under control. Dean just smirked at him, and embarrassment began to burn under his skin as the adrenaline faded, because Jesus Christ, he hadn't even been in the _state_ for a full month before Dean Winchester managed to add his notch to the bedpost.

He waited for Dean to gather his things and saunter off, probably to brag to his cooler-than-thou friends about sucking off the nerdy little prep school boy in the library within twenty minutes of meeting him.

Sure enough, Dean grabbed his textbook and notebook and shoved them into his bag, standing up and slinging it over his shoulder.

Cas looked down at the table, his throat tightening. _Stupid_ , he told himself. _Stupid, stupid. You knew he wasn't actually interested._ He ran a hand through his hair and sighed, then realized Dean was still standing there, an eyebrow raised.

"Well?" Dean said.

"Huh?"

"Are you coming?" he asked, as if it were obvious. "I mean, I know you _were_ coming," he continued with a lopsided grin, "but, uh. Thought maybe we could continue this study session somewhere a little less…" He glanced around pointedly. "I figure Sammy -- my little brother -- he's off doin' nerd stuff 'til the evening, an' my dad ain't home, so…" He trailed off, shifting his feet and looking suddenly shy. "I mean, if you wanna, of course. Or we could just meet up next time -- I swear I won't jump you again, so…"

Cas was on his feet before Dean could finish speaking, shoving his things into his bookbag. Dean breathed a sigh of obvious relief, and instantly his shyness melted back into a leer.

"I figure, after all, there's still some prepositions I'm not so clear on," he murmured. "You know… _under_ you, _inside_ me… and definitely your tongue _in_ my mouth."

Cas swallowed, suddenly infinitely grateful for his prep school English class.

**Author's Note:**

> I tried to double-check all the actual grammar, because grammatical errors in a story _about_ grammar are embarrassing, but feel free to let me know if I missed anything!
> 
> Find me on tumblr at [relucant](http://relucant.tumblr.com). I'm nice.


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